hola, esta pregunta es bastante difícil pero está bien, no lo sé, lo siento :) :)
Answer:
Na has atomic number 11
which is less than magnesium has atomic number 12
ANSWER IS D
Explanation:
aluminum or Al is atomic 13 and Ca or calcium is atomic number 20 and rubidium or Rb is atomic number 37
+2, because Beryllium is in the Group II of the periodic table.
Hope this helps!
The formal charge of H = +1, because F in compounds can have only -1.
Answer: Lanthanide and actinide series
Explanation: The elements with partially or fully filled f orbitals belong to f block elements.
f block elements include lanthanides and actinides. They are called so the lanthanides contain the first element named as lanthanum and actinides contain first element named as actinium. They are also called as inner transition elements.
All of them have general electronic configuration:
, where n = 6-7